1. Field of the Invention
The invention relates to a system for calibrating power sensors.
2. Related Technology
The calibration of power sensors for the high-frequency and microwave range is generally implemented through power comparison at a well-matched source. In this context, the sensor to be calibrated and a reference sensor are connected in succession to a signal source. From the ratio between the two measured powers, a correction factor for the device under test is obtained. However, a disadvantage here is that measuring errors occur as a result of mismatching. This results in imprecise calibration results.
For the compensation of the measuring errors resulting from incorrect matching, the use of vectorial network analyzers is also known. Accordingly, the document “The Vector Analyzer Speeds Power-Sensor Calibration Results”, Microwaves & RF, August 1987, discloses the subdivision of the output signal of a signal generator by means of a resistive power splitter. In this context, one branch of the power splitter is connected to an internal reference power sensor. A second branch of the power splitter is connected via a double directional coupler to the test port for a power comparison. The power sensor to be investigated and a reference power sensor are connected in succession to the test port. The coupling branches of the double directional coupler here are connected to a vectorial analyzer for mismatch compensation.
A disadvantage here is that no optimal matching is achieved and accordingly imprecise measuring results are still obtained.